The recent proliferation of, and resulting stiff competition among, wireless communications products have led to price/performance demands on microwave/millimeter-wave antennas that conventional technologies find difficult to meet. This is due in large measure to high material costs and to high losses in the feed network which must be compensated for. Other problems include expensive manufacturing operations such as milling, hand-assembly, and hand-tuning, and the high numbers and required precision of metal and dielectric parts which are needed to construct these antennas.
High-volume manufacturing techniques have reduced the costs of some conventional antennas, such as the patch arrays that are used in wireless telephone systems and the off-axis parabolic dishes that are extensively used for satellite television reception. However, these techniques do nothing to improve the performance of these antennas, nor do they improve the costs of low- and medium-volume antennas. The need for low-cost high-frequency antennas has also been addressed by using "corporate feed" patch arrays printed on PC boards. Problems with this approach include large losses in the feed array, mostly due to dielectric losses in the PC board, and the high cost of the PC board itself. The losses limit the antenna's usefulness and either degrade the net performance or increase the cost of the associated transmitter and/or receiver.